White-LED Voice Transmitter and Receiver

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Components for the transmitter

Normal 1W white LED

Condenser microphone

74HC4046 PLL IC

CA3130 BiMOS Op Amp IC

100 kohm

5 kohm

50 nF

1 kohm

2 Mohm

100 pF (x2)

5.6 kohm (x2)

Components for the receiver

Centronic OSD100-E (Eye-response photodiode)

74HC4046 PLL IC

CA3130 BiMOS Op Amp IC

33 kohm

0.1 uF

240 kohm

5.6 kohm (x2)

100 pF (x2)

10 uF

1 nF

100 kohm (x2)

250 kohm trimpot

Mono audio socket (to speakers)

Two 9V batteries.


Waveforms Taken at White LED Output

Fig. 1. Waveform without voice input.

Fig. 2. Waveform with voice input.

Waveform at the Receiver

Fig. 3. Waveform at receiver output (i.e. at the audio socket).

Circuit Schematics

 

Pictures of the Project

 

 

Video Demonstration

Source : extremecomputation.blogspot.in